Embedded revocation messaging

ABSTRACT

An apparatus stores ( 60 ), transmits ( 1, 1 ′), or receives ( 2 ) a signal ( 5, 5 ′) representing user desired content ( 10, 10′, 10″, 10′″, 62 ) with device revocation information ( 4, 71 ) embedded in the user desired content. In a suitable transmitting embodiment ( 1, 1 ′), watermark content ( 20 ) including the device revocation information ( 4 ) is embedded in the user desired content ( 10, 10′, 10″, 10 ′″) during encoding as an embedded watermark In a suitable receiving embodiment ( 2 ), an embedded watermark ( 20 ) is read from the signal ( 5 ) representing the user desired content ( 10 ). The device revocation information ( 4 ) is extracted from the embedded watermark ( 20 ).

This application relates to the information processing arts. It findsparticular application in the control of dissemination and use ofcopyrighted music and other recorded content through the use of devicerevocation lists, and will be described with particular referencethereto. However, the following will also find application moregenerally in controlling information transfer among networked devices,in providing improved property protection of music, video, software,data, and other information content, in combating proliferation ofviruses and other malicious software code, and in other similarapplications.

Revocation lists are known for controlling the spread of viruses, forlimiting the distribution and use of copyright protection-disablingsoftware, excluding devices that have been tampered with, and the like.Security protocols that employ revocation lists include the X.509authentication structure and the DTCP (also known as 5C) IEEE1394 linksecurity protocol. The revocation list identifies networked machineswhich are regarded as security risks or are otherwise undesirable.Networked devices receive the revocation list and henceforth refuse tocommunicate with devices identified on the revocation list. Preferably,the revocation list is updated or supplemented on an occasional basis toaccount for spreading viruses, newly identified problematic devices, orthe like.

Revocation lists provide relatively straightforward and effectiveprotection against computer viruses and other information content whichis widely regarded as undesirable. Revocation lists are also employed toexclude a user from having access to certain network resources, or toexclude devices from joining a communication. In the computerenvironment, the users of networked devices generally are cooperative inreceiving and storing the revocation lists and the occasional updates orsupplements to the revocation lists.

However, in certain areas, especially in the areas of music and videocopyright protection and other property protection schemes, a problemarises in using revocation lists to enforce such property rights.Certain users of networked devices who want to circumvent copyright orother property protection are unlikely to cooperate in receiving therevocation data. Rather, these users are likely to attempt to blockdistribution of revocation lists, or to attempt to delete revocationlists that are stored on networked devices. Moreover, even users who areindifferent or favorably disposed toward the revocation lists may notreceive or retain them due to the activities of viruses or othermalicious software which act to block transmission and/or storage of therevocation lists.

In the past, hostility and active opposition to revocation listdistribution has been countered using various approaches. In one typicalrevocation list distribution method, when a connection between twodevices is established, the network connection protocol calls for andrequires communication and storage of the revocation list (if a new orupdated revocation list is being distributed) before any other action isallowed. In this way, devices are forced to receive a revocation list. Adevice having received a revocation list will store it and subsequentlyrefuse to communicate with devices on that revocation list.

However, such secured network transmission protocols are not immune tothe countermeasures of hackers who continually work toward developingnew techniques for overcoming these network protocol-based revocationlist distribution techniques. Efforts of hackers may be successful whenthey can readily identify the revocation list in the data stream, andbecause the hackers (or users of devices which have been infected by avirus or other malicious program produced and distributed by a hacker)experience no adverse consequences when the revocation list is removedfrom the data stream.

The present invention contemplates an improved apparatus and method thatovercomes the aforementioned limitations and others.

According to one aspect, an apparatus is disclosed, including a meansfor storing, transmitting, or receiving a signal representinguser-desired content. The signal includes the user-desired content, anddevice revocation information embedded in the user-desired content.

According to another aspect, a method is provided for distributingrevocation information. The revocation information is embedded intouser-desired content.

One advantage resides in integrating a revocation list with contentdesired by the user. In this manner, the user is induced to accept therevocation list as part of the desired content.

Another advantage resides in its capacity for high rate systems tocommunicate large revocation lists which can contain identificationinformation pertaining to a large number of devices.

Yet another advantage resides in distributing the revocation messageover a large portion of musical content or other user-desired content.In this way, the user cannot avoid receiving the revocation message byomitting a small part of the musical or other user-desired content.

Numerous additional advantages and benefits will become apparent tothose of ordinary skill in the art upon reading the following detaileddescription of the preferred embodiments.

The invention may take form in various components and arrangements ofcomponents, in software, and in various process operations andarrangements of process operations. The drawings are only for thepurpose of illustrating preferred embodiments and are not to beconstrued as limiting the invention.

FIG. 1 shows an exemplary three networked devices and schematicallyillustrates transfer of a revocation list between two devices, andsubsequent refusal of content transfer to the third device which isincluded in the revocation list.

FIG. 2 schematically shows components of the device 1 that encode theuser-desired content along with an embedded revocation list.

FIG. 3 schematically shows components of the device 2 that recover therevocation list and optionally decode the user-desired content.

FIG. 4 schematically shows alternative components of the device 1′ thatencode user-desired content along with an embedded revocation list.

FIG. 5 schematically shows an optical compact disk which includes adigital watermark with a revocation list.

FIG. 6 shows an exemplary method for manufacturing the optical compactdisk of FIG. 5.

With reference to FIG. 1, devices 1, 2, 3 communicate audio, video, orother content with one another by a suitable transfer protocol. Suchtransmission can be by an electronic or optical digital communicationnetwork, a wireless network such as Bluetooth, or the like. The device 1has recently received an updated revocation list 4 that includes arevocation of the device 3.

The revocation list 4 can specify the device 3 in a variety of ways. Thedevice 3 can be specifically revoked, that is, the device 3 is uniquelyidentified in the revocation list 4 as a revoked device. Alternatively,a model or manufacturer corresponding to the device 3 can be revoked. Inyet another revocation arrangement, a content transfer protocol,pathway, or the like used to connect the device 3 with the devices 1, 2can be revoked.

The device 1 communicates content 5 to the device 2. The communicatedcontent 5 includes the revocation list 4 embedded in the content 5 insuch a way that the embedded revocation list 4 is not easily removedfrom the content 5 or is removable only with substantial degradation ofthe content. Moreover, the revocation list 4 is preferably divided intosub-lists which are repeated throughout the length of content 5 so thatthe revocation list 4 is substantially received at the device 2 even ifa small portion of the content 5 is discarded.

Subsequent to communication of the content 5, an attempt is made toinitiate a transfer of content 6 from the device 2 to the device 3.However, the device 2 does not transfer content 6 in view of the updatedrevocation list 4 which the device 2 received in embedded form from thedevice 1 during transfer of content 5. The revocation list 4 identifiesthe device 3 as a revoked device (or identifies the device 3 ascommunicating with a revoked communication protocol or pathway, etc.),and so the device 2 does not communicate with the device 3.

Although audio content 5, 6 is described, the content can also be videocontent, data content, software, or the like. Moreover, the informationcan be represented or encoded in any suitable format, such as PCM, MPEG,AC3, DST, MLC, ATRAC, DivX, analog, or the like. The revocation list 4can be embedded in the content in a suitable manner, such as by anembedded watermark, a designated audio or video channel, in a physicalwatermark, embedding in an analog signal, and so forth. The choice ofrevocation list embedding technique will depend on the type of content(audio, video, software, etc.), and the content format.

With reference to FIG. 2, in one exemplary approach the revocation listis embedded in DST encoded audio content 5 via a digital watermark thatcontains the revocation list 4. The watermark optionally containsadditional content such as copyright information. The digital watermarkdoes not affect the audio or other user-desired content, but also is notreadily removed from the content stream 5 without decoding andreencoding the stream. In this exemplary embodiment, the device Iperforms lossless DST encoding of a high fidelity audio stream 10.Encoding of audio is shown by way of illustrative example, althoughencoding of multimedia, video, data, and the like are also contemplated.During the encoding, the revocation list 4 is embedded. The audio streamcan include a plurality of audio channels, for example to transmitstereo or surround-sound audio. Moreover, instead of or in addition toan audio stream, the user-desired content could include video content,data content, or the like.

A framing processor 14 frames the audio stream 10 into data frames forlossless encoding. Preferably, if the audio stream 10 includes aplurality of audio channels, each audio channel is separately framed bythe framing processor 14. In one suitable embodiment, a constant framelength of 37,362 bits per frame is used. However, different framelengths can be used to optimally balance encoding performance and otherfactors. For each frame output by the framing processor 14, an encodingparameters processor 16 computes suitable encoding parameters. Intypical lossless encoding schemes, the encoding parameters processor 16computes predictive parameters that are used in the encoding toapproximate the frame contents. Various filtering processes are known inthe art for generating a good set of predictive parameters. Suchfiltering is computationally intensive, and the encoding performance isnot critically dependent upon using fully optimized predictiveparameters. Hence, typically the encoding parameters processor 16computes predictive parameter values that provide efficient, but notoptimal encoding performance.

Because precisely optimized values of the predictive parameters is notcritical, these parameters can be modified to encode watermark content20 without substantially degrading the efficiency of the losslessencoding. The watermark content 20 includes at least the revocation list4. Preferably, a sub-lists generator 18 divides the revocation list intosub-lists that are distributed through the watermark content 20, andhence are ultimately distributed through the DST content stream 5. Thesub-lists generator 18 optionally also duplicates the revocation list(or sub-lists thereof) to ensure that the content stream 5 has embeddedrevocation information extending throughout the content stream 5.

A watermark encoder 22 modifies the predictive parameters in apredetermined manner to encode the watermark content 20. For example, aleast significant bit of one or more of the predictive parameters can beset to one or zero corresponding to one bit of the watermark content 20.This small change in one or a few parameter values generally does notsignificantly change the subsequent lossless encoding efficiency. Inanother suitable modification, an additional dummy predictive parameteris selectively added so that the number of predictive parameters (evenor odd) corresponds with one bit of the watermark content 20. Similarly,in yet another embodiment one predictive parameter is selectivelydeleted so that the number of predictive parameters (even or odd)corresponds with one bit of the watermark content 20. Otherpredetermined modifications of the predictive parameters can be used toencode the watermark content 20.

A lossless frame encoder 24 encodes the frame using the modifiedpredictive parameters output by the watermark encoder 22. In onesuitable lossless encoding scheme, a residual is computed thatcorresponds to a difference between the frame value and a valuepredicted using the predictive parameters. For good predictiveparameters, this residual contains much less relevant information, andcan be efficiently encoded. The residual is suitably entropy-encoded.The encoded content along with the predictive parameters are arrangedinto a lossless coded frame by a lossless coded frame constructer 26.Preferably, the predictive parameters are processed by a compressor 28using an efficient compression algorithm prior to incorporation into thelossless coded frame. The lossless coded frame includes the compressedpredictive parameters, the encoded content output by the frame encoder24, and suitable control information (for example a total number ofpredictive parameters and/or a frame length) in a predetermined format.The lossless coded frame enters the DST stream 5 for transmission to thedevice 2.

With reference to FIG. 3, the DST stream 5 is received at the device 2and processed by a lossless coding frame processor 30 that extracts thelossless coding frames from the DST content stream 5 for decoding. Aframe components analyzer 32 separates out the compressed predictiveparameters and the lossless encoded data components. The compressedpredictive parameters are transmitted to an encoding parametersdecompressor 34 for decompression to recover the predictive parametervalues. A watermark content extractor 36 recovers the watermark content20 including the revocation list 4 from the predictive parameters. Thewatermark content 20 is recoverable without decoding the audio content.This allows the revocation list to be recovered even if the contentstream 5 is stored in encoded form at the device 2 without immediatelydecoding and playing the audio content. Moreover, if the transfer rateof the content stream 5 exceeds the decoding speed, the watermarkcontent can be extracted while the audio content is buffered fordecoding.

To recover the audio content, a lossless frame decoder 40 decodes theencoded data components using the predictive parameters recovered by theparameters decompressor 34 to recover the audio stream 10.

The digital watermark content 20 including the revocation list 4 arelogically integrated with the high fidelity audio stream 10. Althoughthe DST digital watermark is typically regarded as a fragile watermark,those skilled in the art will recognize that in practice modifying theintegrated DST data stream to remove the watermark while retaining avalid high fidelity audio DST stream involves a substantial amount oftime, effort, and cost. Moreover, the revocation list 4 is preferablybroken into independently readable sub-lists, each of which isintegrated into one or a few lossless coded frames. In this way, therevocation list cannot be avoided by omitting a small amount of thecontent stream 5.

With reference to FIG. 4, another suitable device 1′ embeds watermarkcontent 20 including the revocation list 4 with a multi-channel audiostream. The audio stream includes audio channel 0 10′, audio channel 110″, and so forth through audio channel n 10′″. Each audio channel 10′,10″, 10′″ is processed by a framing processor 14′, 14″, 14′″ andlossless encoded through the entropy encoding stage by lossless encoders44′, 44″, 44′″. As is known in the art, entropy encoding typicallyoutputs the residual (e_(i)) and a probability signal (p_(i)). Theresidual and probability signals are multiplexed and arithmeticallyencoded by a MUX/arithmetic encoder 46. The predictive parameters arecompressed by a compressor 28′, and combined with the multiplexed andencoded data into a lossless coded frame by a lossless coded frameconstructer 48 for transfer via the content stream 5′.

To embed the watermark 20 including the revocation list 4, at least onebinary bit of watermark content 20 is included as an input to theMUX/encoder 46. For encoders that require paired bit input data, thewatermark bit is preferably paired with one of the probability signalbits, for example paired with the bit p_(n). At the receiving device,the DST stream 5′ is demultiplexed and arithmetically decoded to recoverthe watermark 20. As with the approach of FIGS. 2 and 3, the contentstream 5′ does not need to be lossless decoded to recover the revocationlist 4.

DST digital watermarks provide a relatively large messaging bandwidth.For an exemplary 75 frames/second transfer rate with 15 bits encoded perframe (for example, corresponding to an audio stream 10 includingfifteen lossless encoded audio channels with each channel having oneembedded watermark bit) a watermark transfer data rate of about 1kbit/sec is obtained.

In a three minute song, this results in a corresponding digitalwatermark capacity of 180 seconds times 1 kbit/second=180 kbits or about22 kbytes. For a typical device identifier length of 8 bytes and asignature length of 128 bytes (that is, a signature of a licenseauthority which is typically required to demonstrate authenticity of thedistributed revocation list) the portion of the digital watermarkcorresponding to a three minute song can encode a revocation listidentifying approximately 2800 devices (that is, 22 kbytes divided by 8bytes per device identifier).

Embodiments including embedding of revocation list information in awatermark of a DST encoded audio stream, and embedding of revocationlist information using a designated audio channel of an encodedmulti-channel audio stream are described herein by way of example.However, those skilled in the art can readily adapt the describedembodiments for use with other types of information content and othertypes of encoding. For example, the embedded watermark approach isreadily adapted for revocation list distribution in watermarks ofencoded video streams. Similarly, an unused audio or video channel of amultimedia content stream can be used to transmit embedded revocationlist information. Software and data compression technologies cansimilarly incorporate embedded revocation lists. Revocation listinformation can be incorporated as a dedicated “mute” audio channel ofDVD video. The mute channel is encoded using PCM, MPEG, AC3, or anotheraudio encoding supported by DVD, and is ignored when the DVD is played.However, this approach has a disadvantage if the encoding iscomputationally complex in that the watermark is usually not recoverablewithout fully decoding the audio content. Meridian lossless packing(MLP) lossless encoding, which has been selected for DVD-audio, isreadily adapted for embedding a revocation list.

In these embedding methods, the revocation list is preferably dividedinto revocation device sub-lists that are distributed substantiallyco-extensively with the video or audio content. The lists can beredundantly repeated multiple times so that the user cannot avoid therevocation list by omitting receipt, playback or other accessing of alimited portion of the user-desired programming.

With reference to FIG. 5, yet another exemplary embodiment, in which arevocation list is embedded in a digital watermark of an optical compactdisk 60, is described. The optical compact disk 60 can be a DVD type ofdisc including high fidelity audio content 62 that is encoded byoptically reflective pits disposed on or in the disk 60. The reflectivepits encoding the high fidelity content 62 extend across andsubstantially fill a central portion of the compact disk 60. The regionof high fidelity audio content 62 is represented by texturing in FIG. 5.In a suitable encoding, the high fidelity audio content 62 is encoded inthe lengths of the optically reflective pits while the digital watermark64 is encoded in pit widths.

The watermark 64 is preferably substantially coextensive with the highfidelity audio content 62. In FIG. 5, an exemplary spatial extent ofencoded data of the digital watermark 64 on the disk 60 is schematicallyindicated by inner and outer dashed circumferential boundary lines. Thewatermark 64 includes a revocation list which is preferably divided intoredundantly replicated sub-lists distributed throughout the disk 60. Thewatermark 64 optionally also includes other information such ascopyright information In operation, a user plays high fidelity audiocontent 62 of the compact disk 60 on a playback device (not shown). Ifthe playback device is a compliant device respective to the revocationlist, the playback device simultaneously reads the watermark 64 duringplayback of the high fidelity audio content 62. If the revocation listcontained in the watermark 64 post-dates any revocation lists currentlystored on the compliant playback device, the revocation list of thewatermark 64 replaces the older stored revocation list.

Although an exemplary optical disk 60 is described here, revocationinformation can similarly be distributed by distributing othernon-volatile storage media on which is stored user-desired content withthe embedded revocation information. For example, solid-statenon-volatile memory units, magnetic disks, and the like on which theuser-desired content with embedded revocation information is stored canbe distributed.

With reference to FIG. 6, a suitable method 70 for mass-producing theoptical compact disk 60 is described. A revocation list 71 is divided 72into a plurality of revoked device sub-lists 74. The device sub-lists 74are optionally combined with copyright information 75 or otheradditional watermark content, and the watermark information is encoded76 and a target reflective pit width is computed 78. Similarly, the highfidelity audio content 62 is encoded 80 and a target reflective pitlength is computed 82.

The computed target pit length and width are used to modulate 86 a laserthat records the reflective pits that encode the high fidelity audiodata stream. The pits are formed 88 on a glass substrate disk to definea glass master 90. The glass master 90 is used to mass-produce 92commercial optical compact disks, such as the disk 60, which are usuallyplastic disks with reflective optical coatings. Optionally, themass-production 92 further includes formation of a conventional redbooklayer for backward compatibility with older CD players.

Preferably, the revocation list 71 is updated on an occasional or morefrequent basis by producing an updated glass master 90 in accordancewith the relevant process operations of the method 70. The revocationlist 71 is updated, for example, to include new devices that have beenidentified as being non-compliant with the selected content reproductionmanagement protocol. In this manner, the compact disk manufacturercontinually produces compact disks with music offerings that containup-to-date revocation lists.

Compliant devices automatically receive an updated revocation list eachtime a new compact disk containing updated or supplementary revocationlist information is played.

Embodiments embedding revocation information into audio streams and intophysical medium watermarks have been described. However, it will beappreciated that revocation information can be similarly embedded anddistributed by other devices or media which transmit, receive, or storevarious types of user-desired audio, video, data, software, or othercontent. Employment of less fragile digital watermarks than the DSTwatermarks described herein makes it more difficult to remove theembedded revocation list. However, less fragile digital watermarkstypically have less data capacity and hence can store fewer revokeddevice identifications. Moreover, instead of using a digital watermark,the revocation information can be encoded in a mute channel or otherpathway provided by the encoding technology and comporting with the typeof content being processed.

The invention has been described with reference to the preferredembodiments. Obviously, modifications and alterations will occur toothers upon reading and understanding the preceding detaileddescription. It is intended that the invention be construed as includingall such modifications and alterations insofar as they come within thescope of the appended claims or the equivalents thereof.

1. An apparatus including: a means (1, 1′,2, 60) for storing,transmitting, or receiving a signal (5,5′) representing user-desiredcontent, the signal including: the user-desired content (10, 10′, 10″,10′″, 62), and device revocation information (4, 71) embedded in theuser-desired content.
 2. The apparatus as set forth in claim 1, whereinthe means (1, 1′, 2, 60) for storing, transmitting, or receivingincludes a means (1, 1′) for transmitting, and the means (1; 1′) fortransmitting includes: a means (18) for generating watermark content(20) associated with the user-desired content, the watermark content(20) including the device revocation information (4).
 3. The apparatusas set forth in claim 2, wherein the means (1,1′) for transmittingfurther includes: a means (14, 14′, 14″, 14′″, 16, 24, 26, 44, 44′, 44″,44′″) for encoding the user-desired content (10, 10′, 10″, 10′″); and ameans (22, 46) for embedding the watermark content (20) into the encodeduser-desired content as an embedded watermark.
 4. The apparatus as setforth in claim 1, wherein the means (1, 1′, 2, 60) for storing,transmitting, or receiving includes a means (2) for receiving, and themeans (2) for receiving includes: a means (32, 34, 36) for reading anembedded watermark (20) included in the signal (5) representing theuser-desired content (10), the embedded watermark including the devicerevocation information (4).
 5. The apparatus as set forth in claim 4,wherein the means (2) for receiving further includes: a means (32, 34,40) for recovering the user-desired content (10) from the signal (5). 6.The apparatus as set forth in claim 1, wherein the means (1, 1′, 2, 60)for storing, transmitting, or receiving includes a means (60) forstoring selected from a group consisting of: an optical disk (60), amagnetic disk, and a non-volatile solid-state memory.
 7. The apparatusas set forth in claim 1, wherein the device revocation information (4,71) is arranged into a plurality of independent revocation sub-lists(74) that are distributed across the user-desired content (10, 10′, 10″,10′″, 62).
 8. The apparatus as set forth in claim 7, wherein the devicerevocation information (4, 71) is encoded pervasively through theuser-desired content (10, 10′, 10″, 10′″, 62).
 9. The apparatus as setforth in claim 1, wherein the device revocation information (4, 71) isencoded into a watermark (20, 64).
 10. The apparatus as set forth inclaim 1, wherein the means (1, 1′, 2, 60) for storing, transmitting orreceiving stores, transmits or receives a signal (5, 5′) including theuser-desired content arranged in a format selected from a groupconsisting of: PCM, MPEG, AC3, DST, MLC, ATRAC, DivX, and analog. 11.The apparatus as set forth in claim 1, wherein the user-desired contentincludes digital video content, and the device revocation information isembedded in the digital video.
 12. The apparatus as set forth in claim1, wherein the means (1, 1′, 2, 60) for storing, transmitting, orreceiving includes a means (60) for storing which includes anon-volatile storage medium (60) on which the user-desired content (62)is encoded as a selected modulation of a property of the storage mediummaterial, the selected modulation including a first modulation aspect(82) encoding the user-desired content (62) and a second modulationaspect (78) encoding the device revocation information (71).
 13. Theapparatus as set forth in claim 12, wherein the non-volatile storagemedium (60) is an optical disk (60), the selected modulation includesreflective pits formed on or in the optical disk, and the first andsecond modulation aspects include pit characteristics.
 14. The apparatusas set forth in claim 1, wherein the means (1, 1′, 2, 60) for storing,transmitting, or receiving includes a means (1) for transmitting whichincludes: a framing means (14) for framing the user-desired content(10); a parameter computing means (16) for computing predictiveparameters for each frame; a means (22) for modifying the predictiveparameters to embed the device revocation information (4); and anencoding means (24) for encoding the frame using the modified predictiveparameters.
 15. The apparatus as set forth in claim 1, wherein the means(1, 1′, 2, 60) for storing, transmitting, or receiving includes a means(2) for receiving which includes: a parameter extracting means (32, 34)for extracting predictive parameters of a lossless coded frame thatencodes the user-desired content (10); and a means (36) for recoveringthe device revocation information (4) encoded in the predictiveparameters.
 16. The apparatus as set forth in claim 1, wherein theuser-desired content is a multi-channel audio stream (10′, 10″, 10′″),and the means (1, 1′, 2, 60) for storing, transmitting, or receivingincludes a means (1′) for transmitting which includes: a means (14′,14″, 14′″, 44′, 44″, 44′″) for lossless coding each audio channel; and ameans (46, 48) for combining lossless coded data corresponding to themultiple channels into lossless coded frames, the means for combiningembedding the device revocation information (4) into the lossless codedframes.
 17. A method for distributing revocation information (4), themethod including: embedding the revocation information (4) intouser-desired content (10, 10′, 10″, 10′″).
 18. The method as set forthin claim 17, wherein the embedding includes: dividing a list of revokeddevices into a plurality of sub-lists; and embedding each sub-list intothe user-desired content such that the sub-lists are substantiallycoextensive with the user-desired content.
 19. The method as set forthin claim 17, wherein the embedding includes: generating watermarkcontent (20) including the device revocation information (4); andembedding the watermark content (20) into user-desired content as anembedded watermark.
 20. The method as set forth in claim 19, wherein theembedding further includes: encoding the user desired content (10, 10′,10″, 10′″), the watermark content being embedded into the user-desiredcontent during the encoding.
 21. The method as set forth in claim 17,wherein the embedding includes: embedding the revocation information (4)pervasively through the user-desired content (10, 10′, 10″, 10′″). 22.The method as set forth in claim 17, wherein the embedding includes:selecting predictive parameters for encoding the user-desired content(10); modifying the predictive parameters to encode at least a portionof the revocation information (4) in a predetermined manner; andlossless encoding at least a portion of the user-desired content (10)using the modified predictive parameters.
 23. The method as set forth inclaim 17, wherein the user-desired content is a multi-channel audiostream (10′, 10″, 10′″), and the embedding includes: lossless codingeach audio channel (10′, 10″, 10′″); and combining lossless coded datacorresponding to the multiple channels (10′, 10″, 10′″) into losslesscoded frames, the combining also embedding the device revocationinformation (4) into the lossless coded frames.
 24. The method as setforth in claim 17, further including: communicating the user-desiredcontent (10, 10′, 10″, 10′″) and the embedded revocation information (4)simultaneously.
 25. The method as set forth in claim 24, furtherincluding: extracting the revocation information (4) from thecommunicated user-desired content (10).
 26. The method as set forth inclaim 25, wherein the extracting includes: extracting an embeddedwatermark (20) from a received data stream (5); and extracting thedevice revocation information (4) from the watermark (20).
 27. Themethod as set forth in claim 25, wherein the communicated user-desiredcontent (10) is lossless coded, and the extracting includes: extractingpredictive parameters of a lossless coded frame; and recovering therevocation information (4) encoded in the predictive parameters.
 28. Themethod as set forth in claim 24, wherein the communicating includes:distributing a non-volatile storage medium (60) on which is stored theuser-desired content with the embedded revocation information.